fix: syncToErp 商品单价为空时从 Product.retailPrice/price 回退

- 单价优先级: 补货明细 unitPrice > 商品 retailPrice > 商品 price
- 三者均无有效值时抛出明确的业务异常
- 修复 ERP 因 price=0 返回必填参数未填的问题

Co-Authored-By: Claude <noreply@anthropic.com>

haha-service/src/main/java/com/haha/service/impl/ReplenishmentOrderServiceImpl.java

@@ -391,7 +391,19 @@ public class ReplenishmentOrderServiceImpl extends ServiceImpl<ReplenishmentOrde
                         "商品「" + item.getProductName() + "」ERP商品编码未找到");
             }
 
-            BigDecimal price = item.getUnitPrice() != null ? item.getUnitPrice() : BigDecimal.ZERO;
+            // 单价优先级: 补货明细 > 商品零售价(Product.retailPrice) > 商品售价(Product.price)
+            BigDecimal price = item.getUnitPrice();
+            if (price == null || price.compareTo(BigDecimal.ZERO) <= 0) {
+                if (product != null && product.getRetailPrice() != null && product.getRetailPrice() > 0) {
+                    price = BigDecimal.valueOf(product.getRetailPrice());
+                } else if (product != null && product.getPrice() != null && product.getPrice() > 0) {
+                    price = BigDecimal.valueOf(product.getPrice());
+                }
+            }
+            if (price == null || price.compareTo(BigDecimal.ZERO) <= 0) {
+                throw new BusinessException(400,
+                        "商品「" + item.getProductName() + "」无有效单价，请先在补货明细中填写单价或确保商品有零售价");
+            }
             BigDecimal quantity = BigDecimal.valueOf(item.getPlannedQuantity() != null ? item.getPlannedQuantity() : 0);
 
             OrderGoods goods = OrderGoods.builder()